Abstract

The increased backscattering from liquid–solid interface at the Rayleigh angle is a well‐known indication of leaky Rayleigh wave generation. A comprehensive experimental study [de Billy etal., J. Acoust. Soc. Am. 72, 1018 (1982)] showed much stronger backscattering signals than predicted later by theoretical work based on back reflection. It was later demonstrated [P. B. Nagy and L. Adler, J. Acoust. Soc. Am. 85, 1355 (1989)] that back reflection is negligible in the backward signal, which is simply backscattering from material in homogeneities greatly enhanced by surface wave generation. In this work, recent theoretical developments using second‐order perturbation theory was adapted to study backscattering from liquid–solid rough interfaces. It was shown that at the Rayleigh angle there is an increased backscattering independent from the rms roughness. Theoretical results were experimentally verified. [Work supported by the Office of Naval Research contract N00014‐88‐K0452.]